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To market, to market.

Rigid and flexible plastic packaging, the largest markets in the plastics industry, are more than ever driven by technology. Challenges involve expanding requirements for packaging functionality, lightweighting, recycling, cost reduction, and visual appeal.

Among the varied plastic packaging materials, polyethylene is far and away the front runner. Still a newcomer to the plastics industry in 1941, polyethylene went to war in wire and cable and radar. In 1995, in addition to its impressive growth in many other markets, polyethylene, with its countless rigid and flexible applications, is king of the mountain built by the burgeoning packaging industry.

In 1993, rigid bottles, jars, food containers, buckets, and shipping containers, and the varied applications of flexible packaging accounted for 34.3% of total thermoplastic resin usage. Of the thermoplastic resins used in packaging, 65.4% of the products were made of polyethylene; 12.0% of polystyrene; 9.1% of polypropylene; 8.6% of PET; 3.2% of PVC; and 1.7% of others. Of the polyethylene portion, in 1994, HDPE sales represented 46%; LDPE, 30%; and LLDPE, 24%, for a total of 26.1 billion lbs.

At least 50% of polystyrene's total 6 billion lb usage in 1994 went into packaging or disposable food serviceware. Much of this volume results from the fact that polystyrene is the quickest plastic to heat up and cool down, thus enabling more economical processing. But the fastest growing segment in the overall packaging market is the PET bottle, which has doubled in volume over the last five years to 1.9 billion lbs in 1994. Successful curbside recycling of PET bottles has enhanced their appeal in the eyes of many environmentally conscious consumers.

The major thermoplastics in the packaging markets have achieved many innovations involving basic packaging concepts, technology that provides significantly improved packaging properties, lightweighting, recycling, and greater cost-effectiveness. The different plastics are also used in combination with other packaging materials (such as aluminum foil in flexible food packaging), and demonstrate a continuous evolution in the technology's functionality as well as solid waste aspects. Seventy-five percent of supermarket bags are now made of polyethylene; one truckload of the plastic bags can transport what normally requires six truckloads of an equivalent number of paper bags. The food service, food retail, cosmetics, and home-management industries, among many others, are all major beneficiaries of modern packaging.

Across the product line

Procter & Gamble uses more than 100 million lbs/yr of HDPE for rigid and flexible packages across its product line. This volume includes the market areas of laundry and cleaning; food and beverages; and paper, beauty, and health care products. Significantly smaller volumes of polypropylene are used for closures; PET for bottles; and PVC for thermoforming of blister packs for pharmaceuticals and cosmetics.

Tom Rattray, associate director, Environmental Quality, Worldwide, says that source reduction and recycling initiatives are among the company's continuing objectives. Concentrated laundry detergents, for example, require less product per laundry load and thus have the effect, on an overall basis, of reducing packaging requirements. Lightweighting by downgauging is achieved by precise parison control in blow molding, application of new extruder technology, and use of materials with improved properties.

Citing customer preference of refills, for convenience and for achieving net reductions in individual packaging for a given product, Rattray foresees thinner rigid refill bottles of more material-efficient design, and a continuing gradual conversion from rigid to flexible packages. However, he adds that further refinements are necessary in the opening and dispensing features of the flexible packaging. There is also a gradual shift from corrugated paper packaging to the use of returnable plastic shipping containers, and from steel to blow-molded or rotomolded plastic drums and pails, with an emphasis on less net packaging to do the job.

Some typical examples of Procter & Gamble's packaging efforts are its Tide detergent refill bags; the material optimization of the Crisco PET bottle, which reduces material by about 30%; and the company's stand-up flexible dentifrice tubes, which also save about 30% in required material, and feature an improved laminated construction that provides a "spring-back" quality after it is squeezed.

In essence, Rattray believes, things are moving along well in the packaging design and source reduction area, but overall recycling could stand a nudge forward.

Some winners

Innovations in flexible packaging technologies, closures, substrates, and printing, and advances in source reduction have achieved improved materials and product protection, reduced costs, opened new markets, and advanced customer convenience. Glenn E. Braswell, president of the Flexible Packaging Association (FPA), notes that new technology is answering "some of the most esoteric packaging demands in history." The trade association represents converters and suppliers to the industry; FPA members manufacture 85% of the flexible packaging produced in the U.S.

Some of the FPA's Top Packaging Awards for 1994 demonstrate significant technological responses to market challenges. A retort pouch for the food-service industry from American National Can Co., for example, could be the first commercially viable use, outside the military, of retort packages for low-acid foods. The technical challenge was to create a foil-containing flexible material that could withstand the retort requirements of hermetic sealing and heating to 250 [degrees] F, and meet U.S. Food & Drug Administration standards. By designing the bottom web of the 12.5- x 13-inch package to draw to approximately 1.5 inches deep, American National Can created a cavity large enough to hold the same amount of food as the No. 10 can it replaces. The package's commercial possibilities are significantly enhanced by its ability to be filled on existing form/fill/seal equipment at conventional filling speeds. (Past attempts to fill flat, 12- x 15-inch bags, presealed on three sides, failed because of unacceptably slow line speeds.) The untilled pouches weigh 75% less than the cans, and a case of six filled pouches takes up 20% less space than a case of six cans.

Another package design, called the Valu-Loc TarnishGuard bag from Com-Pac International, Inc., which the company says will last 15 to 30 years, protects precious metals, jewelry, fine art pieces, and sensitive parts from corrosion, and eliminates need for repolishing. A proprietary material neutralizes corrosive gases before they can react with the precious metals. Previous technology used oil-based volatile corrosion inhibitors, which absorbed the corrosive gases rather than neutralizing them. The bag contents had to be coated with an oil, which then had to be removed by solvents. In addition, shelf life was only about six months. With the new technology, the bags are produced with a low-density polyethylene-based structure, with solid-state non-volatile pieces of material bonded into the polymer chain at the atomic level. Successfully protecting precious metals by means of the innovative technology opens the market to manufacturers as well as consumers.

Tide and Cheer low-density polyethylene refill bags produced by Paramount Packaging Corp. use 80% less packaging than the carton alternative and incorporate 25% post-consumer recycle content. Holding 9.5 lbs of granular detergent, the bags fill to a basically square form that permits easy stacking on store shelves. Bold and bright colors are achieved by trapping about 80% fluorescent ink coverage within the laminate structure. The buried gravure printing eliminates scuffing or abrasion problems. An additional challenge was the control required over the post-consumer recycled-content material to secure a clean, smooth surface finish.

In another award-winning example, Jergens Lotion's new stand-up pouch, the first on the market to hold and protect hand lotion, uses a proprietary combination of resins and barrier films to create a chemical-barrier web that prevents the product from discoloring the packaging and seeping out. The 12.5-fluid-ounce pouch reduces package weight by 75% compared with the 10-fluid-ounce bottle, and offers an improved "billboard" effect over the cylindrical bottle.

A package for the protection of radioactive cesium iodide blocks, the ClearFoil Pouch from Rollprint Packaging Products, Inc., is one of the first commercial uses of glass-coated film in the U.S. The silicon-oxide-coated polyester laminate protects the radioactive cesium iodide crystals in a manner that allows them to be visually inspected while still in their package, thus reducing the risk of accidental radiation exposure. Since the crystal blocks attract and absorb high amounts of moisture, the package requires outstanding moisture barrier capability. Created for the Fermi National Accelerator Laboratory, more than 3000 of these crystals are used as building blocks to form a solid wall against which scientists collide subatomic particles at nearly the speed of light in experiments on the nature of matter.

Property balance

Polypropylene, with its inherent "living hinge," made a large impression in the world of plastic design in the mid-1970s in applications like the pump sprayer, and in general in the quest for parts consolidation and product compactness. The success of the living hinge, a result of the material's flexibility, toughness, and overall balance of properties, has been repeated in packaging applications as containers and closures of many different types. Of a total of 9.7 billion lbs of polypropylene usage in 1994, one billion was used in packaging for injection molding and thermoforming of rigid containers and closures, and blow molding of bottles. Of this total, about 80% used the injection molding process, taking advantage of the material's melt flow while retaining its balance of properties, notably its stiffness and impact strength. In a yogurt container application, for example, the wall thickness before lightweighting was 0.27 inch. While the material is thinwalled down to 0.20 inch, representing an approximate 35% weight reduction, sufficient strength and stiffness are retained to permit safe stacking of containers on retailers' shelves. Apart from the rigid packaging segment, 710 million lbs of oriented polypropylene film and 172 million lbs of the unoriented material were used in flexible packaging in 1994.

David McKeeman, product manager, Packaging, Montell USA, Inc., says that in 1994, the market for polypropylene injection molded containers grew by 155 million lbs, largely because of the material's ability to be thinwalled without significant sacrifice of performance. McKeeman adds that Montell's commercial availability of direct reactor-produced 35 dg/10 min melt-flow-rate copolymer, compared to more typical melt flow rates of 12 to 20, has been instrumental in fostering market expansion. Wall thicknesses down to 0.018 inch are now achievable, as against the more typical 0.027 inch of a few years ago.

Commenting that packaging has been polypropylene's fastest growing market area, McKeeman also adds that Montell will make its new SC 912 polypropylene commercially available this month. The material features, as an extension of reactor technology, a faster cycling 70 melt index, and it will be processable in existing machines and tooling at temperatures 15 [degrees] C to 20 [degrees] C lower. Also coming from Montell as "a potential competitor for PET" in the plastic bottle market is a new polypropylene grade with exceptional clarity, the result of a change in formulation and refinements in processing by injection stretch blow molding.

Double-digit growth

The application of polyesters in rigid packaging produced by extrusion and thermoforming started in the mid-to-late 1980s and has grown consistently on an annual double-digit basis to more than 250 million lbs/yr. Improvements in cost/performance and in the range of polyester materials available to meet different market needs are creating expectations of continued growth in the near future. Phillip Crowder, market segment manager, Specialty Packaging Plastics, Eastman Chemical Co., says that the material's competitive position is being improved by minimizing materials required for a given package, notably through downgauging, and by optimizing processing by reducing the time for drying the polyester. An even further possibility involves enhancing extruders to eliminate altogether the separate cost-adding step of drying.

Eastman's family of polyester materials for rigid packaging includes its APET clear amorphous grade (for use to about 140 [degrees] F), for applications such as general-purpose blister packages, clear drinking cups, and dell containers; its CPET higher-temperature opaque crystalline grade, for use to 350 [degrees] F to 400 [degrees] F, for dual-oven-able trays; Eastar PETG 6763, the company's proprietary copolyester grade (for use to 140 [degrees] F) that is highly modified with cyclohexanedimethanol (CHDM), a crystallization inhibitor, for more stringent packaging requirements in markets such as medical and electronic; and PCT, with a temperature capability of 160 [degrees] F, notably for specialty packaging.

Tooling for thinwalling

Thinwall rejection molders are continuing to lightweight parts for cost reduction and for environmental considerations, and all components of the system are being improved to meet this challenge, according to Jordan Robertson, strategic planning, Thinwall Packaging, Husky Injection Molding Systems Ltd. Accumulator-assisted injection is being used with high cavitation precision molds and easier flowing resins to achieve reduced part weight. New developments in hot runner design and balance are also making molds easier to fill.

Recent resin technology provides stronger properties, which offer the potential for even thinner walls. Packaging machines will require more clamp force as well as higher injection speeds and pressures to meet molders' needs. Developmental gating techniques such as multiple bottomgating and rim gating may also become important solutions for lightweighting in the future.

New machine developments at Husky, for example, will focus on higher productivity. Cycle times will be reduced by the higher clamp speeds, while other new features will increase up-time and reduce scrap rates. For certain high-volume products, four-level stack molds are dramatically improving productivity. This technology can now be considered for lids and shallow containers.

Further reductions in part cost are being achieved by increased automation in downstream product handling. Husky is developing a system for stacking and boxing containers in its Advanced Manufacturing Center in Bolton, Ontario. Containers are removed from the mold via swing chutes that ensure clean, oriented parts. As the parts exit the chute, they are conveyed to a vertical upstacker, and the stacks are loaded into a box by a gantry-style robot.

Today's thinwall injection molders will become more competitive in the international packaging market as a result of these improvements in system productivity, automation, and the continued lightweighting of parts.

Downgauged thermoforming

Thermoformed packages with specified sidewall thicknesses as low as 0.005 inch are being used on high-speed filling equipment in the food and personal care industries by the billions of units every year. Tony Mack, vice president, Development & Quality, Fabri-Kal Corp., says that both thermoforming machine manufacturers and processors are advancing the state of the art to allow for ever wider sheet and higher cavitation molds with greater automation for product handling. Cavitation is routinely at three digits for rigid packages up to 16 oz in size, and unit output per machine is measured in the hundreds of millions annually.

Machines are now available to thermo-form polypropylene at high throughputs, making it competitive with polystyrene and polyethylene packages, while taking advantage of polypropylene's high heat, stiffness, and clarity characteristics. Thermoforming of amorphous polyester (APET), a material that cannot be processed by injection molding, is growing rapidly to take advantage of its high clarity, low permeation rates, toughness, and recyclability. APET is being used as a premium rigid packaging material.

Tooling design and faster thermoforming cycles are optimized with enhanced cooling efficiency, easy stripping features, and application of advanced computer imaging and machining techniques. The result is improved dimensional uniformity of the lighter-weight thinwall containers.

Packaging legislation

The American Plastics Council's state government affairs staff, in conjunction with The Society of the Plastics Industry's member companies, plastics processors, and allies, has had some success in its efforts "to assure a measure of restraint and reason in the drafting of packaging legislation." Roger Bernstein, senior director, Government Affairs and Regional Operations, APC, reports that in 1994, a lobbying program opposed the passage of some 180 restrictive legislative proposals in 32 states. The APC monitored more than 800 legislative proposals of interest to the plastics industry in 41 states and Puerto Rico, about the same as in 1993. In the process, the APC had numerous challenges. Bernstein says that "all were successfully managed by the APC state government affairs staff and its coalition partners."

California and Oregon have been particularly active in passing laws concerning rigid plastic containers In 1994, the APC applied its efforts especially in states where legislation mandated that rigid plastic containers must either achieve a 25% recycling rate; contain 25% recycled material; be reduced 10% by weight or volume; or be reusable. After two years of development, final regulations in California's packaging law were approved last November. Persistent lobbying by affected parties and continuous negotiations resulted in more reasonable and realistic regulations, according to Bernstein. California's Integrated Waste Management Board was persuaded to narrow its "overly broad" definition of a rigid plastic packaging container. In addition, food service packaging was exempted, and retailers are no longer held responsible for compliance. Also, by allowing corporate averaging (as is now done in implementation of the automotive industry's CAFE standards for gas mileage), the law gives companies greater flexibility in complying with the requirements for recycled, reusable, or reduced packaging.

Oregon's final regulations were adopted last October. APC's staff, plastics companies, and their customers worked closely with the state's Department of Environmental Quality (DEQ) to develop regulations that were reasonable and that reflected the law's intent. Nevertheless, Bernstein comments that "a DEQ anti-plastics bias resulted in an overly broad definition of a rigid plastic container, thus bringing some point-of-sale packaging, domed lids, and trays under the law." The rules do not allow corporate averaging, nor do they include exemptions for containers subject to certain federal regulations. But tubes and blister packs were eliminated from the definition of a rigid plastic container; and the DEQ worked cooperatively with APC's technical staff in determining a more realistic recycling rate methodology. With increased collection and processing of post-consumer rigid plastic containers, the 25% recycling rate requirement was achieved by the compliance deadline of Jan. 1, 1995. Oregon's DEQ also stated that enforcement action for the law, based on a manufacturer's compliance status, will begin on Jan. 1, 1996, instead of a year earlier.

"Chasing arrows"

In 1994, a San Diego-based "Take the Wrap" movement encouraged legislators in California, Washington State, and Colorado to challenge laws that require the current "chasing arrows" voluntary resin identification coding system, originally designed by SPI, claiming it falsely suggests that all containers bearing the code are recyclable. Use of the code is now mandated in 39 states.

APC and industry allies helped defeat the bills attempting to modify the code. For example, in California, anti-code legislation was proposed that outlawed the use of the chasing arrows triangle symbol or similar logos. APC's opposition campaign, combined with a product company lobbying effort and an appeal for national uniformity, helped persuade the sponsor to drop the bill prior to any committee vote.

Similarly, the Washington State bill, which would have banned the arrows from the code and required use of an international coding system, was rescinded following testimony by APC, plastics industry customers, and local plastics processors. The Colorado bill to ban the chasing arrows triangle, or a similar symbol that implied recyclability, would have repealed the state's coding law. APC, national and local food and product manufacturers, and Colorado processors joined in a coalition to oppose the bill.

A major factor was that lawmakers in California, Washington, and Colorado were influenced to vote against changes to the code because of ongoing national negotiations between SPI and the National Recycling Coalition (NRC) on possible improvements to the system. The NRC board rejected a joint proposal of the negotiating teams, thus eliminating the possibility of consensus on any changes to the current coding system.
COPYRIGHT 1995 Society of Plastics Engineers, Inc.
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Title Annotation:plastics packaging
Author:Wigotsky, Victor
Publication:Plastics Engineering
Date:Jun 1, 1995
Previous Article:Annual report 1994.
Next Article:Structure/property relationships in polyolefins made by constrained geometry catalyst technology.

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